1. Field of the Invention
The present invention relates to an ink jet printer head, and more particularly to an improvement of the nozzle surface of an ink jet printer head that selectively attaches ink drops onto a recording tedium.
2. Description of the Related Art
These days, high speed printing, low noise and high print quality are demanded of ink jet printers, and moreover high performance is demanded of ink jet printer heads. The state of the nozzle surface of an ink jet printer head is extremely important for satisfying these demands.
Ink, paper dust and the like may become attached to the nozzle surface, and if such attachments are present, then when an ink drop is ejected from the nozzle, the ink drop is attracted by the attachments and is ejected in a direction different to the original ejection direction; if the amount of such attachments is large, then ink drops may not be formed at all. In order to eliminate these problems, it is considered important to give the nozzle surface an ink-repellent property (i.e. a water-repellent property). By giving the nozzle surface an ink-repellent property, attachment of ink, paper dust and the like can be reduced. Moreover, in an ink jet printer head, it is also important to suppress deterioration of the ink drop ejection performance.
As art for giving a nozzle surface an ink-repellent property and suppressing deterioration of ink drop ejection performance, an ink jet printer head in which a water-repellent layer comprising a metal layer and a sulfur compound layer is formed on the nozzle surface has been proposed (International Patent Publication No. WO97/27059).
However, in the case of the ink jet printer head disclosed in the above-mentioned International Patent Publication, an alkanethiol compound, a dithiol compound having a single aromatic ring, or the like is used as the sulfur compound that forms the sulfur compound layer. Due to insufficient intermolecular cohesion of this sulfur compound, there is a risk of the sulfur compound layer deteriorating through external factors such as mechanical friction leading to a drop in the performance of the sulfur compound layer, which is a problem in terms of the reliability of the printer head.
An object of the present invention is thus to provide a highly reliable ink jet printer head exhibiting a water-repellent property, low deterioration of ink drop ejection performance, and high friction resistance, along with a method of manufacturing this ink jet printer head.
The inventors of the present invention carried out various studies, and as a result discovered that an ink jet printer head in which a layer consisting of a thiol compound having a certain specific structure is formed on top of a metal layer formed on the nozzle surface of the printer head is capable of achieving the above object.
The present invention was arrived at based on the above findings. The present invention provides an ink jet printer head wherein ink drops are ejected from nozzles formed in a nozzle surface, and wherein the ink jet printer head has a metal layer comprising metal formed on the nozzle surface and a self-organized film layer comprising a polycyclic thiol compound formed on top of the metal layer.
Moreover, the present invention also provides a method or manufacturing the above-mentioned ink jet printer head, comprising the steps of forming a metal layer on the nozzle surface of a nozzle member, and immersing the nozzle member on which the metal layer has been formed in a solution in which a polycyclic thiol compound has been dissolved.
Moreover, the present invention also provides the polycyclic thiol compounds represented by undermentioned general formulae (I) or (II): 
wherein Cf is CF3(CF2)n, CF3(CF2)n(CH2)m, (CF3)2CF(CF2)n, (CF3)2CF(CF2)n(CH2)m, (CF3)3C(CF2)n or (CF3)3C(CF2)n(CH2)m, n is an integer greater than or equal to 0, m is an integer greater than or equal to 1, k is an integer greater than or equal to 3, p is an integer greater than or equal to 1, and 1 is an integer from 1 to 4.